Endoscopic microsurgery, including procedures performed by way of endoscopic instruments such as gastroscopes, colonoscopes, laparoscopes, and the like, may be preferred as an alternative to open surgery due to the many advantages attributed to such “minimally invasive” techniques such as shortened hospital stays, reduced recovery time, reduced risk of complications, and diminishment of the amount of and/or visibility of scarring caused by a surgical intervention. In many endoscopic procedures, as in open surgery, there are instances where a surgeon may desire to repair damaged or diseased tissues by apposing the tissues together using a suture. However, the suturing devices, stapling devices, and other fastener applicators that have been developed to aid surgeons in performing open surgery generally cannot be easily redesigned to be passed through a flexible endoscopic instrument, which may have a working channel having an internal diameter in the range of about 2.5 to about 4.0 millimeters.
Some gastric restriction procedures utilize a series of fasteners that are coupled together by a suture used to cinch and pull the fastened tissue together. Suture coupled fasteners offer the advantage of allowing the fasteners to be applied to each wall of the stomach separately and then to be cinched together using the suture after the fastener applying device is removed. In order to apply staples, on the other hand, folds must be created in each wall to engage and pull the tissue together, thus requiring that the staples be inserted through four walls of tissue.
To address these problems, various suture anchors and applicator devices have been developed to permit surgeons to endoscopically emplace sutures within tissues. Such suture anchors may be deployed using applicator devices that are inserted within and extended through the working channel of an endoscope, carrying a suture anchor to the site of the repair. Such applicators typically include a cannulated needle portion which permits the surgeon to penetrate the tissues adjacent to diseased or damaged tissue and deploy the suture anchor within, or preferably onto a distal surface of, the tissue to be apposed in repair.
The suture anchor is generally attached to a distal end of a suture, with the bulk of the suture extending alongside or within a portion of the applicator device, and with a proximal end of the suture trailing outside the endoscopic instrument. After deploying the suture anchors, the surgeon may appose the tissue by applying tension to the proximal ends of the sutures, thereby manipulating the suture anchors and the surrounding tissues, and secure the apposed tissue by advancing a series of half hitches towards the repair site using a knot pusher device. Alternately, the surgeon may thread the trailing ends of the sutures through one of a number of types of knotting elements and associated knotting element applicators, feed the applicator through the flexible endoscope towards the apposed tissue, and “fire” the applicator to fix or “knot” the sutures in place with the knotting element. Examples of such suture locking and knotting devices are disclosed in U.S. Patent Application Publication No. US 2007/0270907 A1, to Michael J. Stokes et al., entitled “Suture Locking Device”, filed May 19, 2006, and U.S. Patent Application Publication No. US 2007/0270889 to Sean P. Conlon et al., entitled “Combination Knotting Element and Suture Anchor Applicator”, filed May 19, 2006, the disclosures of each said published applications being herein incorporated by reference in their respective entireties.
While suture-coupled fasteners may be more advantageous than staples in some applications, slack or loops of excess suture can form as the surgeon is attaching the fasteners to the opposed walls of the stomach. For a gastric restriction procedure to be successful, for example, the suture must be tightly cinched to pull the gastric walls together so that the reduced volume of the patient's stomach can be maintained. If any slack or loose loops of suture are present, the stomach will expand and the restriction will not be effective. Thus, the surgeon must maintain tension on the suture as the fasteners are being applied and the sutures are “knotted” or otherwise fastened together. Moreover, because of the relatively long distances traveled by endoscopic devices, user forces are not generally transmitted in a one-to-one fashion with respect to time and magnitude. As a result, tactile feedback to the surgeon is generally poor. This makes tension control of resulting stitches difficult. Too much tension can cause tissue necrosis, while insufficient tension can cause peritonitis or other issues associated with a loose stitch, such as malfunction of the suturing device. These problems are also encountered when suturing within the gastrointenstinal (“GI”) tract wherein two pieces of sutures are locked together, during general tissue approximation.
Consequently a need exists for devices that can manage and/or indicate the amount of tension applied to a suture prior to the sutures being locked together.
The foregoing discussion is intended only to illustrate some of the shortcomings present in the field of the invention at the time, and should not be taken as a disavowal of claim scope.